/**
 * $RCSfile$
 * $Revision$
 * $Date$
 *
 * Copyright 2003-2007 Jive Software.
 *
 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jivesoftware.smack.util;

import java.io.*;
import java.util.*;

/**
 * An ObservableWriter is a wrapper on a Writer that notifies to its listeners
 * when writing to character streams.
 * 
 * @author Gaston Dombiak
 */
public class ObservableWriter extends Writer {

	Writer wrappedWriter = null;
	List listeners = new ArrayList();

	public ObservableWriter(Writer wrappedWriter) {
		this.wrappedWriter = wrappedWriter;
	}

	public void write(char cbuf[], int off, int len) throws IOException {
		wrappedWriter.write(cbuf, off, len);
		String str = new String(cbuf, off, len);
		notifyListeners(str);
	}

	public void flush() throws IOException {
		wrappedWriter.flush();
	}

	public void close() throws IOException {
		wrappedWriter.close();
	}

	public void write(int c) throws IOException {
		wrappedWriter.write(c);
	}

	public void write(char cbuf[]) throws IOException {
		wrappedWriter.write(cbuf);
		String str = new String(cbuf);
		notifyListeners(str);
	}

	public void write(String str) throws IOException {
		wrappedWriter.write(str);
		notifyListeners(str);
	}

	public void write(String str, int off, int len) throws IOException {
		wrappedWriter.write(str, off, len);
		str = str.substring(off, off + len);
		notifyListeners(str);
	}

	/**
	 * Notify that a new string has been written.
	 * 
	 * @param str
	 *            the written String to notify
	 */
	private void notifyListeners(String str) {
		WriterListener[] writerListeners = null;
		synchronized (listeners) {
			writerListeners = new WriterListener[listeners.size()];
			listeners.toArray(writerListeners);
		}
		for (int i = 0; i < writerListeners.length; i++) {
			writerListeners[i].write(str);
		}
	}

	/**
	 * Adds a writer listener to this writer that will be notified when new
	 * strings are sent.
	 * 
	 * @param writerListener
	 *            a writer listener.
	 */
	public void addWriterListener(WriterListener writerListener) {
		if (writerListener == null) {
			return;
		}
		synchronized (listeners) {
			if (!listeners.contains(writerListener)) {
				listeners.add(writerListener);
			}
		}
	}

	/**
	 * Removes a writer listener from this writer.
	 * 
	 * @param writerListener
	 *            a writer listener.
	 */
	public void removeWriterListener(WriterListener writerListener) {
		synchronized (listeners) {
			listeners.remove(writerListener);
		}
	}

}
